The invention relates generally to a system for nondestructive inspection of parts, and more particularly, to a system for detecting flaws in parts employing eddy current method.
The presence of surface cracks and subsurface flaws in metallic structures, such as engine blades, have the potential to lead to failure of an engine. Harsh environment and extreme operating envelope for aircraft engines cause early failures in critical area of engine components. Various inspection methods have been developed and used heretofore for crack and flaw detection with varying degrees of success.
Several prior art inspection methods are deployed for a fine crack detection of aircraft body and engine components. One of methods is fluorescent penetrant inspection (FPI) that applies penetrant material over suspected areas and look for indications with ultraviolet light. The FPI is effective and widely used in aerospace industry and doesn't require stringent inspection environment such as close contact or curvature of parts, but its detectability isn't as good as eddy current inspection. The other is an eddy current inspection that investigates an indication of depth to ascertain crack and flaw severity. The eddy current probes require close proximity to the part. It also requires complex manipulators and inspection plan to follow contoured part geometry to maintain 100% inspection coverage and avoiding lift-off variation between the probes and the. Full coverage with eddy current probes is very time consuming. Spot checking may miss critical crack and defect areas.
Consequently, a need still exists for an improved inspection technique that will provide a solution to the aforementioned problem without introducing any new problems in place thereof.